Your Sister's Sister (2011)

Iris invites her friend Jack, who's mourning his brother's death, to her father's cottage for some alone time to recuperate, but they discover that Iris' sister Hannah is already there recovering from a recent break-up. One whole bottle of tequila later, Jack and Hannah wake up to find Iris at the door. All three have secrets they're trying to keep and feelings they're trying to sort out.